mathball/lib/frequency/index.js

A JavaScript library for Competitive Programming

'use strict';

var validate = require('../validation/frequency');

/**
* Find the occurence count of a phrase
* @param {string} str
* @param {string} occurance
*/
var findStrOccurence = function findStrOccurence(str, occurance) {
  var count = 0;
  var flag = -1;

  do {
    flag = str.indexOf(occurance, flag + 1);
    if (flag !== -1) {
      count++;
    }
  } while (flag !== -1);

  return count;
};

/**
 * Frequency
 *
 * `frequency()` accepts two arguments and return the occurance of second argument in first
 * @param {string|number|string[]|number[]} arg - Accepts either a String or an Array
 * @param {string|number} occurence - The phrase or array item you want to find
 */
module.exports = function (arg, occurence) {
  validate(arg, 'frequency');

  if (arg && arg.constructor === Array) {
    return arg = arg.filter(function (val) {
      return val === occurence;
    }).length;
  } else {
    return findStrOccurence(arg, occurence);
  }
};